Upgrade Rev1 CB030 to 16-bit CF Interface

Introduction

The rev 1 CB030 has 8-bit wide CF interface. It is possible to upgrade it to 16-bit wide interface by hooking up CF's high byte to 68030's D16-D23, and by shifting the address lines to A1-A3. The CPLD needs to be changed to account for 16-bit port; the CF driver will need to change to accommodate 16-bit wide port and different address map.

www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_cb030_cb030_rev1_dsc_56670409.jpg

www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_cb030_cb030_rev1_dsc_56660409.jpg

Engineering change procedures

Add 8 data lines

Connecting CF's data 8 to data 15 to 68030's data 16 to data 24 through 100 ohm series terminating resistors

www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_cb030_cb030_rev1_cf16_ec_cf16_data_mod_solder.jpg

  1. Pins 4, 6, 8, 10, 12, 14, 16, 18 of CF adapter are removed by heating each pin with a solder gun until solder melt and pull out the pin with a tweezer.
  2. cut out the plastic body of the 8 removed pin to create room for series terminating resistors
  3. Install 8 1/10 watt 100 ohm resistors in place of the removed pins. These are series terminating resistors.
  4. Connect pin 4 of CF adapter to pin 3 (68030 D[16]) of SIMM socket with a 30 gauge wirewrap wire. Connect the remaining 7 data lines as follow
  • pin 6 of CF adapter to pin 5 (68030 D[17]) of SIMM socket,
  • pin 8 of CF adapter to pin 7 (68030 D[18]) of SIMM socket,
  • pin 10 of CF adapter to pin 9 (68030 D[19]) of SIMM socket,
  • pin 12 of CF adapter to pin 21 (68030 D[20]) of SIMM socket,
  • pin 14 of CF adapter to pin 23 (68030 D[21]) of SIMM socket,
  • pin 16 of CF adapter to pin 25 (68030 D[22) of SIMM socket,
  • pin 18 of CF adapter to pin 27 (68030 D[23]) of SIMM socket.

Address lines modification

  1. Cut address lines A0, A1, A2 at location shown. (click the picture for detailed photo) www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_cb030_cb030_rev1_cf16_ec_cf16_addr_cut.jpg
  2. Connect pin 35 of CF adapter (formerly address A0) to pin 11 of U2 (address A1)
  3. Connect pin 33 of CF adapter (formerly address A1) to pin 10 of U2 (address A2)
  4. Connect pin 36 of CF adapter (formerly address A2) to pin 9 of U2 (address A3).

www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_cb030_cb030_rev1_cf16_ec_cf16_addr_add_comp.jpg

www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_cb030_cb030_rev1_cf16_ec_cf16_addr_mod_solder.jpg

Enable CF interrupt

www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_cb030_cb030_rev1_cf16_ec_cf16_irq_mod.jpg

  1. Connect pin 31 of CF adapter to middle pin of T7
  2. Install a 10K pull down resistor from the middle pin of T7 to ground

CF interrupt priority is fixed at level 1, autovector.

CPLD Update

Updated CPLD is required to enable CF interrupt and change CF port size to 16-bit wide.

CP/M68K BIOS Update

Updated CP/M68K BIOS is required to work with 16-bit wide CF interface

Updated EPROM image

This updated EPROM image contains rev 0.5 CB030bug, EhBasic, and CP/M68K BIOS/CCP/BDOS for 16-bit CF interface

Updated CF Memory Map

0xFFFFE000 is CF data register, 16-bit

0xFFFFE002 is CF feature/error register, 8-bit

0xFFFFE004 is CF sector count register, 8-bit

0xFFFFE006 is CF sector register, 8-bit

0xFFFFE008 is CF track register, low byte, 8-bit

0xFFFFE00A is CF track register, high byte, 8-bit

0xFFFFE00C is CF head/drive register, 8-bit

0xFFFFE00E is CF status/command register, 8-bit

CFdata  equ $FFFFE000       * CF data register
CFerr   equ $FFFFE002       * CF error reg
CFsectcnt equ $FFFFE004      * CF sector count reg
CF07    equ $FFFFE006       * CF LA0-7
CF815   equ $FFFFE008       * CF LA8-15
CF1623  equ $FFFFE00A       * CF LA16-23
CF2427  equ $FFFFE00C       * CF LA24-27
CFstat  equ $FFFFE00E       * CF status/command reg

Updated schematic

This is the updated schematic reflecting all the above changes.

builderpages/plasmo/cb030/cb030_rev1/16-bit_cf_upgrade.txt · Last modified: 2020/04/13 22:49 by plasmo
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